Where a number of wireless networks which offer similar service capabilities are available for public access in the same geographic area, it is desirable to promote efficient spectrum loading, minimal call costs to the user, and competition between network operators. This is true in the user's "home" area as well as when the user roams to other areas. Efficient spectrum utilisation is promoted because lightly loaded systems can attract customers towards it. Also, overloading of networks, particularly packet data networks, can be avoided. By selecting the operator providing the desired service and quality of service at the lowest cost, the call costs tend to be minimised for the user, at least for outgoing calls. Finally, having dynamic costing structures promotes competition.
For future communications systems it is anticipated that two classes of service may exist. The first is a limited set of standardised core services such as telephony. The second is a set of operator-specific services which may be created by an operator and which are quite specific to the operator's network. A user in a home network may normally subscribe to a preferred operator or set of operators which provide mobility management and which together provide the user's desired service mix. An emerging requirement of third generation systems is that users when roaming should be able to access the same service set, even if the visited systems do not normally provide all the services.
Accordingly, there is also a need for a method and apparatus for selecting a communication system to minimize tariff rates.